U.S. Pat. No. 5,375,410 describes a combined combustion and steam turbine power plant that includes a steam turbine unit, a boiler unit for supplying a first supply of steam to the steam turbine unit, and a gas turbine (combustion turbine) unit including a heat recovery steam generator for providing a second supply of steam to the steam turbine unit. The prior art plants are started by first starting the gas turbine unit, thereby establishing exhaust airflow through the exhaust gas duct structure. Once the airflow is established through the duct structure, a portion of the airflow can be directed to the boiler to support the operation of the boiler. Combustion in the boiler is supported by the “clean” exhaust from the gas turbine combustor, which still contains a significant amount of oxygen in spite of the combustion occurring within the gas turbine combustor. The compressor of the gas turbine unit thus provides the motive force for the boiler combustion air, and operation of the entire plant is predicated upon the availability of the gas turbine unit. The boiler unit cannot be operated separately from the gas turbine unit.